PSI for 19's
'RX-EIGHT'
Joined: Feb 2004
Posts: 2,768
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Seeing as the 8 is rear wheel drive, you might want to maybe reverse the pressures (i.e front higher, rear lower) and drop them down a bit.
Might I suggest 32psi front and 30psi rear?
Try it out and play around with it, tire pressure is often a matter of personal choice.
Might I suggest 32psi front and 30psi rear?
Try it out and play around with it, tire pressure is often a matter of personal choice.
Registered User
Joined: Aug 2003
Posts: 839
Likes: 2
Be wary of load ratings...some of those low profile tires have very poor load ratings...which means you have to put alot of pressure in the tire to make sure it doesn't tear off the rim.
Aka the lower the profile and lower the load rating, the higher the pressure. Technically with some tires you should be running in the mid-upper 40 psi's to get the same load ratings as stock.
These guys have a nice overall chart of tire load ratings which your can x-ref with the new tires.
http://www.sportcompactcarweb.com/tech/0208scc_tires/
Quote from a Toyo Employee...
Thread which the quote is sitting
http://forum.mazda6club.com/index.ph...pic=23786&st=0
Aka the lower the profile and lower the load rating, the higher the pressure. Technically with some tires you should be running in the mid-upper 40 psi's to get the same load ratings as stock.
These guys have a nice overall chart of tire load ratings which your can x-ref with the new tires.
http://www.sportcompactcarweb.com/tech/0208scc_tires/
Quote from a Toyo Employee...
PLEASE NOTE: THE FOLLOWING INFORMATION WAS OBTAINED FROM TOYO'S ELECTRONIC FITMENT GUIDE. IT MAY BE POSSIBLE TO RUN LOWER PRESSURES THAN STATED BELOW, HOWEVER, PLEASE EXERCISE CAUTION AS IT IS GENERALLY PREFERABLE TO RUN A LITTLE HIGHER PRESSURE THAN TO RUN UNDERINFLATED. IF YOU HAVE SPECIFIC QUESTIONS REGARDING YOUR VEHICLE, PLEASE PM ME. THANKS!
I haven't seen any threads on this, so if I'm repeating info already discussed, I apologize, but it's information worth repeating anyway. I want to bring to everyone's attention the importance of correct air pressure, especially in plus applications (meaning if you have 18 or 19 inch wheels).
When you go to a larger rim diameter, you are making the air chamber smaller, thus requiring additional air in the tire to carry the same load. For example, if your Mazda 6 came with the P215/50R17 tires, your minimum air pressure stated on the door placard is 32 psi. Same is true with the 16 inch tires.
Now, let's say you've upgraded to 235/40R18s. Hopefully, you're using a reinforced construction tire like the Toyo Proxes 4 (load index 95). You'll now need to have at least 33 psi to maintain the same load. Not bad, not a big difference.
But let's say 235s are too wide for you because your wheel offset makes that size rub, so you're using 225/40R18s. If you're using a reinforced size (load index 92), you'll now have to run 38 psi to maintain the same load! Many owners continue to run the original 32 psi and wonder why their tires wear out quickly. Running low air pressure creates heat which accelerates wear on the tire.
If you do not have tires with a load index of at least 91, your tires may not properly carry the load of your car!
Perhaps you've got 19s on your beloved 6. Hopefully, you've got at least a 235/35R19 91V (reinforced). You'll have to run 39 psi to maintain the same load as the oe tire at 32 psi!
Even if you've simply gone to a wider tire on the oe wheels, you need to make sure you've got the right air pressure. A 225/45R17 (94 load index) requires a minimum of 35 psi.
If you've gone to anything smaller than the above listed sizes (like 215/40R18 or 225/35R19) you should probably inflate your tires to the max air pressure listed on the sidewall. Chances are, though, you have a tire that won't carry the load of your vehicle properly.
Also, check your air pressure at least once a month as air will seep out at the rate of 1 psi per month. Your air pressure will also change with the ambient air temperature. For every 10 degrees of ambient air change, your tires will lose/gain 1 psi. If the last time you checked your air was in June and the average temperature was 80 degrees and now its October and now its 60 degrees, you've lost 6 psi of air (4 months + 20 degrees ambient air change)! Make sure you check the air when the tires are cold. Do yourself a favor and get a quality gauge. Thanks for looking!
I haven't seen any threads on this, so if I'm repeating info already discussed, I apologize, but it's information worth repeating anyway. I want to bring to everyone's attention the importance of correct air pressure, especially in plus applications (meaning if you have 18 or 19 inch wheels).
When you go to a larger rim diameter, you are making the air chamber smaller, thus requiring additional air in the tire to carry the same load. For example, if your Mazda 6 came with the P215/50R17 tires, your minimum air pressure stated on the door placard is 32 psi. Same is true with the 16 inch tires.
Now, let's say you've upgraded to 235/40R18s. Hopefully, you're using a reinforced construction tire like the Toyo Proxes 4 (load index 95). You'll now need to have at least 33 psi to maintain the same load. Not bad, not a big difference.
But let's say 235s are too wide for you because your wheel offset makes that size rub, so you're using 225/40R18s. If you're using a reinforced size (load index 92), you'll now have to run 38 psi to maintain the same load! Many owners continue to run the original 32 psi and wonder why their tires wear out quickly. Running low air pressure creates heat which accelerates wear on the tire.
If you do not have tires with a load index of at least 91, your tires may not properly carry the load of your car!
Perhaps you've got 19s on your beloved 6. Hopefully, you've got at least a 235/35R19 91V (reinforced). You'll have to run 39 psi to maintain the same load as the oe tire at 32 psi!
Even if you've simply gone to a wider tire on the oe wheels, you need to make sure you've got the right air pressure. A 225/45R17 (94 load index) requires a minimum of 35 psi.
If you've gone to anything smaller than the above listed sizes (like 215/40R18 or 225/35R19) you should probably inflate your tires to the max air pressure listed on the sidewall. Chances are, though, you have a tire that won't carry the load of your vehicle properly.
Also, check your air pressure at least once a month as air will seep out at the rate of 1 psi per month. Your air pressure will also change with the ambient air temperature. For every 10 degrees of ambient air change, your tires will lose/gain 1 psi. If the last time you checked your air was in June and the average temperature was 80 degrees and now its October and now its 60 degrees, you've lost 6 psi of air (4 months + 20 degrees ambient air change)! Make sure you check the air when the tires are cold. Do yourself a favor and get a quality gauge. Thanks for looking!
http://forum.mazda6club.com/index.ph...pic=23786&st=0
Last edited by crossbow; Oct 22, 2004 at 06:11 AM.
Boost needed
Joined: Dec 2003
Posts: 2,557
Likes: 0
From: San Jose, CA
don't think it would slow a car too much, but most 19s are heavier than the stock ones and heavy is no good. General concensus it doesn't help performance wise to have bigger size rims but much can be said about the opposite.
Registered User
Joined: Jan 2003
Posts: 1,232
Likes: 2
From: Houston
When people talk about wheel weight they almost always forget about tire weight.
Typically with quality rims the extra weight of the larger rim is offset by the reduced weight of the lower profile tire. The performance pretty much stays the same.
-Mr. Wigggles
Typically with quality rims the extra weight of the larger rim is offset by the reduced weight of the lower profile tire. The performance pretty much stays the same.
-Mr. Wigggles
Registered User
Joined: Aug 2003
Posts: 839
Likes: 2
Wiggles,
Except through physics...you'd know that even though the tire weight is less, its now farther away from the hub of the wheel...greatly increasing its effect on the overall rotational mass.
A few magazines have run studies, and going to 19 inch rims from something like a 17 or 16, can add as much as 0.3 tenths to your 1/4 mile time. The 8's got 18's stock, so it probably won't make as large a difference. Then of course, you could put on some forged 17's with low profile rubber, getting a final gearing advantage and massive unsprung weight loss vs a set of cast 19's.
Regardless, if you are running extremely low profile rubber, make sure the tire can handle the load, and your running the correct psi to compensate. Stock psi pressues don't work for non stock configurations.
Except through physics...you'd know that even though the tire weight is less, its now farther away from the hub of the wheel...greatly increasing its effect on the overall rotational mass.
A few magazines have run studies, and going to 19 inch rims from something like a 17 or 16, can add as much as 0.3 tenths to your 1/4 mile time. The 8's got 18's stock, so it probably won't make as large a difference. Then of course, you could put on some forged 17's with low profile rubber, getting a final gearing advantage and massive unsprung weight loss vs a set of cast 19's.
Regardless, if you are running extremely low profile rubber, make sure the tire can handle the load, and your running the correct psi to compensate. Stock psi pressues don't work for non stock configurations.
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